Aftermath: On Marriage and Separation, By Rachel Cusk

The opprobrium that the author is receiving because of this honest and heart-wringingly sad memoir is unwarranted

Rachel Cusk's writing has quietly thrilled me for years with its intelligence, perception and understated power: ordinary people's flaws are depicted vividly yet without fanfare in brittle, brilliant prose. Cusk met with public opprobrium for admitting that she found motherhood difficult – a crude knee-jerk response. The anger met by any suggestion that aspects of motherhood can be challenging is disturbing and counter-productive: frayed mothers may become reluctant to admit difficulties, spurn sources of help, and crack. Cusk, though, is far from a non-coping mother; her love for her daughters radiates through the bleak moments of this book.

Aftermath is the story of the months after the breakdown of Cusk's marriage. It was Cusk who asked to separate, but the initiator of a break-up also feels sadness as well as guilt, remorse and doubt. The self control – there is no shrieking or ululating – may precipitate accusations of coldness. But Aftermath has a similar air of devastation to Joan Didion's Blue Nights. Both deal with bereavement of sorts, both avoid speaking about the lost person either through self-preservation, or the numbness of grief. Cusk is also protecting her children.

The catalyst for Cusk's decision to end her marriage was an inability to share equally the responsibilities of earning, childcare and housework. Despite loving her children, Cusk yearned for her old identity. Women leaping from interesting jobs to the world of motherhood, with its limited adult conversation, may understand Cusk's frustration. Yet when her husband gave up his law job to enable Cusk to return to work, she resented supporting him financially while still doing her share of chores.

Much of the anger at the excerpt of Aftermath published in another newspaper seems to be at Cusk's selfishness in wanting, initially, to deny her husband shared custody. This was indeed monstrously self-centred, but I admire Cusk for being honest. The urge to own those one loves is a human instinct, albeit an unacceptably egocentric one.

Cusk was also outraged at having to support her husband financially after the divorce. This is more understandable, and shows how men have traditionally been disadvantaged by divorce, being obliged to pay for another adult's upkeep.

There is some confused angst about feminism, with Cusk contemplating whether feminists hate femininity, women who don't do paid work, and even men. This is the kind of extreme thinking that drives school-age girls to view feminism suspiciously. Not all feminists are Angela Dworkin. A feminist is not someone who spurns femininity but one who thinks both genders should have equal opportunities in every field. A true feminist wouldn't disapprove of a woman looking pretty or staying at home to look after kids, any more than she would a man.

Cusk's intellect and love of language occasionally lead to opaque prose ("relentlessly iterative" lacks lucidity; "tenebrous" crops up twice), and the emotional impact dissipates as a consequence. But how wonderful to have a piece on desolation that is not leaking pop psychology, or emoting effusively. And, as always with Cusk, it's exhilarating to feel stimulated, to have fabulous phrases and similes cause pulses of pleasure: "My sins will not devour me but will be dutifully paid off over a lifetime in small increments, like a mortgage."

The parts dealing with the effects of the divorce on Cusk's daughters are heart-wringingly sad. Cusk's protective instinct is vigorous. She feels "a sword through my heart" when the girls cry in the bath; boils with rage if friends ostracise them. She notes that when she takes them to the swings, it's "as though they are wearing masks ... though quite what they are representing – their own unhappiness or mine – I am not sure." An anecdote about a holiday in Devon where the accommodation is hideous is savagely funny; after hours of fretting, Cusk sweeps her daughters away.

Cusk is startlingly insightful in many passages describing her new status as outsider. She likens the experience of seeing nuclear families to looking in through a window from outside. And although the women seem content, occasionally they glance wistfully back.

There is little rancour or bitterness about her ex; an absence of railing acrimony. Her daughters will be able to read this without feeling upset at the depiction of their father. Driving to the doomed holiday, Cusk feels "buoyed up ... by the feeling ... that we have been liberated from the strictures of some authority and are free. I don't identify this authority as my husband: the authority is marriage itself, and in these moments of liberty I feel him to be just as browbeaten by it as me, feel, almost, that I could conscript him into my own escape and re-encounter him there, in non-marriage, both of us free."

The enemy here is not this specific ex, but the general myth of having it all.